Liquid crystal display

ABSTRACT

A liquid crystal display includes: a transparent first substrate placed on the display plane side; a transparent second substrate opposed to the first substrate; a cholesteric liquid crystal that is placed between the first and second substrates and whose selective reflection color is yellow; and a reflector for white/blue display opposed to the second substrate. The angular dependence of scattered light intensity of the reflector for white/blue display is equivalent to the angular dependence of scattered light intensity of the cholesteric liquid crystal.

TECHNICAL FIELD

The present invention relates to a liquid crystal display.

BACKGROUND ART

In recent years, various types of cholesteric liquid crystal displayshave been studied which have a cholesteric liquid crystal layer andrequire neither a backlight nor a polarizing plate. The cholestericliquid crystal layer includes a plurality of rod-like liquid crystalmolecules arranged to form a multilayer structure. The liquid crystalmolecules are arranged so that the alignment is in roughly the samedirection in the planar direction in which each layer spreads and ishelical in the layer stack direction.

Cholesteric liquid crystal in a non-voltage applied state (planar state)selectively reflects light having a specific wavelength (selectivereflection wavelength) corresponding to the chiral pitch (helicalpitch). Cholesteric liquid crystal in a low-voltage applied state (focalconic state) transmits light. Cholesteric liquid crystal displaysdisplay an image by selecting the planar state and the focal conic stateappropriately.

As an example of such liquid crystal displays, Patent Document 1discloses a liquid crystal display element in which a chiral nematicliquid crystal composition that selectively reflects a specific visiblelight wavelength at room temperature is sandwiched between a pair ofsubstrates at least one of which is transparent. An alignmentstabilizing film is formed on each of the substrates, a blue absorptionlayer is placed on the substrate opposing the display plane, the peakreflection wavelength of the selective reflection of the chiral nematicliquid crystal composition is in the range of 570 to 600 nm, the peakreflection wavelength of the blue absorption layer is in the range of450 to 480 nm, and the half-width of a spectral reflection waveformobserved when the liquid crystal layer made of the above liquid crystalcomposition is in the selective reflection state is 95 to 115 nm. Thisdisclosure describes that having this configuration, a large-contrastliquid crystal display element exhibiting good whiteness in mono-colordisplay of white color and another color, and in particular a liquidcrystal display element that can provide good blue/white display and issmall in viewing angular dependence, can be obtained.

Citation List Patent Document

PATENT DOCUMENT 1: Japanese Patent Publication No. P2003-5222

SUMMARY OF THE INVENTION Technical Problem

However, in cholesteric liquid crystal, the proportion of specularlyreflected components is large and hence the reflected light intensityhas angular dependence. Also, the selectively reflected light fromcholesteric liquid crystal, which is based on Bragg reflection, has anature of blue-shifting with light entering obliquely. As for a bluepigment, however, the angular dependence of reflected light intensity issmall.

Hence, when the back surface of the layer of yellow cholesteric liquidcrystal is coated with a blue pigment, or taped with a blue pigment, toattain white/blue display of the device, the blue color will beintensified when viewed at an oblique angle, reducing the contrast ratioof the display.

Solution to the Problem

An object of the present invention is providing a liquid crystal displaycapable of securing good visibility of the display screen when viewed atan oblique angle.

The liquid crystal display of the present invention includes: atransparent first substrate placed on the display plane side; atransparent second substrate opposed to the first substrate; acholesteric liquid crystal that is placed between the first and secondsubstrates and whose selective reflection color is yellow; and areflector for white/blue display opposed to the second substrate,wherein the angular dependence of scattered light intensity of thereflector for white/blue display is equivalent to the angular dependenceof scattered light intensity of the cholesteric liquid crystal.

The “angular dependence of scattered light intensity” described aboverefers particularly to the ratio of scattered light intensity tospecularly reflected light. No scattered light will arise from a perfectmirror. When a predetermined scattering layer is provided, however,light rays other than the specularly reflected light are observed asscattered light.

The expression that “the angular dependence of scattered light intensityof the reflector for white/blue display is equivalent to the angulardependence of scattered light intensity of the cholesteric liquidcrystal” means that the ratio of scattered light intensity to specularlyreflected light of the former is roughly the same as that of the latter.

Having the configuration described above, in which the angulardependence of scattered light intensity of the reflector for white/bluedisplay is equivalent to the angular dependence of scattered lightintensity of the cholesteric liquid crystal material, when the displayscreen is viewed at an oblique angle, the reflected light intensity ofblue color decreases along with blue-shifting of the cholesteric liquidcrystal. Therefore, when the display screen is viewed at an obliqueangle, the cholesteric liquid crystal in the focal conic state hardlyreflects light, and hence the reflectance ratio (contrast ratio) thereofto the blue-shifted blue range of the cholesteric liquid crystal in theplanar state is maintained. Good visibility can therefore be attained.

In the liquid crystal display of the present invention, the reflectorfor white/blue display may include a reflection layer, a scatteringlayer, and a blue transmission layer formed one upon another in thisorder, and the blue transmission layer may be opposed to the secondsubstrate.

Alternatively, in the liquid crystal display of the present invention,the reflector for white/blue display may include a reflection layerhaving a predetermined scattering angle and a blue transmission layerformed one upon the other, and the blue transmission layer may beopposed to the second substrate.

Alternatively, in the liquid crystal display of the present invention,the cholesteric liquid crystal may be aligned in a non-rubbing manner,and the reflector for white/blue display may include a reflection layerand a blue transmission layer formed one upon the other, and the bluetransmission layer may be opposed to the second substrate.

The expression that “the cholesteric liquid crystal is aligned in anon-rubbing manner” indicates that no rubbed alignment film is placed inthe liquid crystal display and hence the cholesteric liquid crystal isnot aligned with the alignment film. In general, in a liquid crystaldisplay, a film for arranging liquid crystal molecules in the liquidcrystal display panel in a fixed direction (alignment film) isnecessary. To impart an alignment property to the film, the film issubjected to rubbing process in which streaks are formed in onedirection with a cloth and the like.

With the configuration described above, the cholesteric liquid crystal,which is aligned in a non-rubbing manner, has a multi-domain structurein the planer state. This permits scattering of light at domainboundaries in the liquid crystal layer. Hence, a simple-structure liquidcrystal display device without the necessity of forming a scatteringlayer can be provided.

In the above configuration, since blue light mirror-reflected inside theliquid crystal display is subjected to Rayleigh scattering in thecholesteric liquid crystal layer in the planar state (short-wavelengthlight is apt to scatter), “blue color” of the reflected light iscombined with “yellow color” of selectively reflected light of thecholesteric liquid crystal layer in the planar state, becoming “whitecolor.” When specularly reflected light is incident and passes through afocal conic region, blue reflected light is directly observed,permitting observation of strong blue color. When it passes through aplanar region, blue reflected light scatters inside the cholestericliquid crystal layer as described above. Therefore, the blue light iscombined with “yellow color” of the selectively reflected light in theplanar region, exhibiting white color. Meanwhile, when scattered lightfrom the surroundings is incident, weak scattered light from theunderlying reflection layer is observed in the focal conic region. Inthe planar region, “yellow color” of selectively reflected light in theplanar state is combined with “blue color” of light from the reflectionlayer scattered inside the planar region, exhibiting white color.

In the liquid crystal display of the present invention, the cholestericliquid crystal may be aligned in a non-rubbing manner, and the reflectorfor white/blue display may include a blue hologram.

With the configuration described above, in which the reflector forwhite/blue display is a blue hologram, the degree of freedom enhances inselection of the reflected light intensity and reflected lightwavelength of the device. Also, the designer can design the visionrestriction of the device freely.

ADVANTAGES OF THE INVENTION

According to the present invention, a liquid crystal display capable ofsecuring good visibility of the display screen when viewed at an obliqueangle can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a liquid crystal display ofEmbodiment 1 of the present invention.

FIG. 2 is a cross-sectional view of a liquid crystal display ofEmbodiment 2 of the present invention.

FIG. 3 is a cross-sectional view of a liquid crystal display ofEmbodiment 3 of the present invention.

FIG. 4 is a cross-sectional view of a liquid crystal display ofEmbodiment 4 of the present invention.

FIG. 5 is a graph showing the relationship between the angle from thezenith and the reflectance for a reflector for white/blue display and acholesteric liquid crystal layer in Embodiments 1 to 4 of the presentinvention.

FIG. 6 is a schematic view of an optical system for measurement of theangle and the reflectance shown in FIG. 5.

DESCRIPTION OF REFERENCE CHARACTERS

-   10, 20, 30, 40 Liquid crystal display-   11, 31, 41 Liquid crystal display panel-   12, 22, 32, 42 Reflector for white/blue display-   13, 33, 43 First substrate-   14, 34, 44 Second substrate-   15, 35, 45 Cholesteric liquid crystal layer-   16, 26, 36 Reflection layer-   17 Scattering layer-   18, 28, 38 Blue transmission layer-   21 Diffusion mirror surface

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described hereinafter indetail with reference to the accompanying drawings. Note however thatthe present invention is not limited to these embodiments.

Embodiment 1

A liquid crystal display 10 of Embodiment 1 of the present inventionwill be described in detail with reference to the drawings.

(Configuration of Liquid Crystal Display 10)

FIG. 1 is a cross-sectional view of the liquid crystal display 10 ofthis embodiment. The liquid crystal display 10 includes a liquid crystaldisplay panel 11 and a reflector 12 for white/blue display.

The liquid crystal display panel 11 includes a first substrate 13, asecond substrate 14 opposed to the first substrate 13, and a cholestericliquid crystal layer 15 that is placed between the first and secondsubstrates 13 and 14 and includes cholesteric liquid crystal moleculeswhose selective reflection color is yellow.

Each of the first substrate 13 and the second substrate 14 includes atransparent substrate made of glass or a resin such as polycarbonate,polyethylene terephthalate, and polyether sulfone, a transparentelectrode patterned on the transparent substrate, an alignment filmapplied to the surface of the transparent electrode and subjected toalignment treatment such as rubbing, and the like.

As the transparent electrode, a transparent conductive film such as atin oxide film, a zinc oxide film, an indium tin oxide (ITO) film as acompound of indium oxide and tin oxide, and an indium zinc oxide (IZO)film as a compound of indium oxide and zinc oxide may be used.

As the alignment film of the liquid crystal display panel 11, a resinsuch as polyimide, an inorganic evaporated film such as a silicon oxidefilm, and silane-based, ammonia-based, and other surface modifiers maybe placed.

The cholesteric liquid crystal layer 15 includes a plurality of rod-likecholesteric liquid crystal molecules constituting a multilayerstructure. When no voltage is applied across the cholesteric liquidcrystal layer 15, the cholesteric liquid crystal molecules are arrangedin roughly the same direction in the layer direction and arrangedhelically in the layer stack direction (planar state). The cholestericliquid crystal layer 15 in the planar state selectively reflects lighthaving a wavelength near a selective reflection wavelength correspondingto the chiral pitch (helical pitch) of the cholesteric liquid crystalmolecules arranged helically in the layer stack direction, whiletransmitting light having a wavelength that is not near the selectivereflection wavelength. The “selective reflection wavelength” as usedherein refers to a wavelength obtained by multiplying the averagerefractive index of the cholesteric liquid crystal molecules by thechiral pitch (helical pitch) of the cholesteric liquid crystalmolecules, and is synonymous with the “peak wavelength of selectivereflection.”

The cholesteric liquid crystal layer 15 in the low-voltage applied state(focal conic state) transmits incident light in the entire wavelengthband without selectively reflecting light having a wavelength near theselective reflection wavelength. Once the cholesteric liquid crystallayer 15 becomes the focal conic state with application of a lowvoltage, it maintains the focal conic state even after the voltageapplication is stopped. Accordingly, in the liquid crystal display 10having the cholesteric liquid crystal layer 15, power consumption perunit time can be reduced particularly in display of a still image.

As the cholesteric liquid crystal molecules, the following can be used,for example: a nematic liquid crystal composition having a mesogen suchas cyanobiphenyl, phenylcyclohexyl, phenylbenzoate, cyclohexylbenzoate,azomethine, azobenzene, pyrimidine, dioxane, cyclohexylcyclohexane, andtolane with a chiral agent made of a compound having an optically activegroup such as a cholesterol derivative and a 2-methylbutyl group addedthereto.

The reflector 12 for white/blue display includes a reflection layer 16,a scattering layer 17, and a blue transmission layer 18 formed one uponanother in this order, in which the blue transmission layer 18 isopposed to the second substrate 14.

As the reflection layer 16, a plastic film such as a polyethyleneterephthalate (PET) film with a metal such as silver and aluminumevaporated thereon, or a smooth, thin metal film obtained by drawing ametal, such as aluminum foil, for example, is used, forming a mirrorsurface. If the metal (evaporated) surface as the mirror surface issusceptible to deterioration from oxygen, water, and the like, aprotection layer may be formed on the metal (evaporated) surface foranti-deterioration. Such anti-deterioration measures should be takenappropriately depending on the type of the metal and the desireddurability.

As the scattering layer 17, an acrylic diffusion material withmicroparticles mixed therein in a concentration of about 5 wt %, forexample, is formed on the surface of the reflection layer 16 to athickness of about 1 μm.

The microparticles in the scattering layer 17 are preferably spherical,in particular pearl-shaped. As such microparticles, used aremicroparticles of an organic macromolecular compound such as acrylicresin, polyurethane resin, and polystyrene resin, microparticles ofsilicon-containing resin, and microparticles of an inorganic compoundsuch as silica.

The scattering property of the scattering layer 17 can be changed bychanging the particle density and particle size of the microparticles,the thickness of the scattering layer 17, the refractive index of theresin, and the like.

As the blue transmission layer 18, an acrylic resin with a blue pigmentsuch as copper phtalocyanine (CuPc), for example, mixed therein isformed on the acrylic diffusion material.

The angular dependence of scattered light intensity of the reflector 12for white/blue display configured as described above is made equivalentto the angular dependence of scattered light intensity of thecholesteric liquid crystal layer 15. To state specifically, as shown inFIG. 5, the reflector 12 for white/blue display and the cholestericliquid crystal layer 15 exhibit roughly the same relationship betweenthe angle from the zenith and the reflectance.

In the graph shown in FIG. 5, the “angle from the zenith” refers to theangle θ from the line drawn from the light source placed at the zenithwith respect to the reflection plane to the reflection plane (the normalto the reflection place) as shown in FIG. 6, which is a schematic viewof an optical system for measurement of the angle and the reflectanceshown in FIG. 5.

In FIG. 5, while the angular dependence of reflected light intensity ofthe blue pigment constituting the blue transmission layer 18 is small,the angular dependence of reflected light intensity of the reflector 12for while/blue display is large, and the ratio of the scattered lightintensity to the specularly reflected light of the reflector 12 forwhite/blue display is equivalent to that of the cholesteric liquidcrystal layer 15.

(Method for Fabricating Liquid Crystal Display 10) Next, a method forfabricating the liquid crystal display 10 of Embodiment 1 of the presentinvention will be described.

(Formation of Liquid Crystal Display Panel 11)

First, a glass substrate having a size of 365 mm×460 mm and a thicknessof 0.7 mm, for example, is prepared.

A transparent electrode made of ITO, for example, is patterned on theglass substrate, and then an alignment film is applied to the resultantsubstrate.

The surface of the alignment film is then subjected to alignmenttreatment such as rubbing, to form the first substrate 13. Note that athin inorganic film made of silicon oxide may be formed as an insulatingfilm between the alignment film and the ITO.

The second substrate 14 is also formed in a manner similar to thatdescribed above, and then the first substrate 13 and the secondsubstrate 14 are bonded together with spacers made of plastic beadshaving a particle size of about 5 μm, for example, therebetween.

The bonding between the first substrate 13 and the second substrate 14is made by sealing the peripheries of the bonding surfaces of the twosubstrates with epoxy resin and the like.

Yellow cholesteric liquid crystal molecules having a selectivewavelength of about 560 nm, for example, are then injected in the spacebetween the two substrates, thereby obtaining the liquid crystal displaypanel 11.

(Formation of Reflector 12 for White/Blue Display)

A PET film is prepared, and aluminum is evaporated on the surface of thePET film to about 100 nm, for example, to form the reflection layer 16.

An acrylic diffusion material with microparticles mixed therein in aconcentration of about 5 wt %, for example, is applied to the aluminumsurface of the PET film to a thickness of about 1 μm and cured, to formthe scattering layer 17.

An acrylic resin with about 3 wt % of copper phtalocyanine mixed thereinis applied to the acrylic diffusion material to a thickness of about 2μm and cured, to form the blue transmission layer 18, thereby obtainingthe reflector 12 for white/blue display.

Thereafter, the reflector 12 for white/blue display is bonded to thesecond substrate 14 of the liquid crystal display panel 11 fabricated asdescribed above with a transparent adhesive material.

The liquid crystal display 10 is thus completed.

—Operational Advantages of Liquid Crystal Display 10—

According to the liquid crystal display 10 fabricated as describedabove, when light incident from the front is specularly reflected, lightspecularly reflected by the cholesteric liquid crystal layer 15 and bluelight reflected by the back are combined, thereby displaying good whitecolor. Also, in focal conic regions of the cholesteric liquid crystallayer 15, the color of the blue diffusion layer is clearly visible.Hence, good white/blue color is displayed.

As the device is tilted from the front so that the specularly reflectedlight becomes invisible, the liquid crystal reflection color isblue-shifted, reducing the reflectance. At this time, however, since thereflected light intensity of the reflector 12 for white/blue displayalso decreases, the contrast can be kept unchanged although the displaychanges from white/blue to light blue/dark blue.

Embodiment 2

A liquid crystal display 20 of Embodiment 2 of the present inventionwill be described in detail with reference to the drawings.

(Configuration of Liquid Crystal Display 20)

FIG. 2 is a cross-sectional view of the liquid crystal display 20 ofEmbodiment 2 of the present invention. Note that like components asthose of the liquid crystal display 10 of Embodiment 1 described aboveare denoted by the same reference numerals, and description thereof isomitted in this embodiment.

The liquid crystal display 20 includes the liquid crystal display panel11 and a reflector 22 for white/blue display.

The liquid crystal display panel 11 includes the first substrate 13placed on the display plane side, the second substrate 14 opposed to thefirst substrate 13, and the cholesteric liquid crystal layer 15 that isplaced between the first and second substrates 13 and 14 and includescholesteric liquid crystal molecules whose selective reflection color isyellow.

The reflector 22 for white/blue display includes a reflection layer 26having a predetermined scattering angle and a blue transmission layer 28formed one upon the other, in which the blue transmission layer 28 isopposed to the second substrate 14.

As the reflection layer 26, used is a plastic film such as a PET filmwith a metal such as silver and aluminum evaporated thereon, the surfaceof which is embossed to have a predetermined scattering angle. Theresultant reflection layer 26 therefore has a diffusion minor surface21.

If the metal (evaporated) surface as the minor surface is susceptible todeterioration from oxygen, water, and the like, a protection layer maybe formed on the metal (evaporated) surface for anti-deterioration. Suchanti-deterioration measures should be taken appropriately depending onthe type of the metal and the desired durability.

As the blue transmission layer 28, an acrylic resin with a blue pigmentsuch as copper phtalocyanine (CuPc), for example, mixed therein isformed on the acrylic diffusion material.

The angular dependence of scattered light intensity of the reflector 22for white/blue display configured as described above is made equivalentto the angular dependence of scattered light intensity of thecholesteric liquid crystal layer 15, as discussed above with referenceto FIG. 5, for example.

(Method for Fabricating Liquid Crystal Display 20)

Next, a method for fabricating the liquid crystal display 20 ofEmbodiment 2 of the present invention will be described.

(Formation of Liquid Crystal Display Panel 11)

The liquid crystal display panel 11 is fabricated in a manner similar tothat described above in Embodiment 1.

(Formation of Reflector 22 for White/Blue Display)

A PET film is prepared, and then the surface thereof is embossed to havea predetermined scattering angle.

Aluminum is then evaporated on the embossed PET film surface to athickness of about 100 nm, for example, to form the reflection layer 26having the diffusion minor surface 21.

An acrylic resin with about 3 wt % of copper phtalocyanine mixed thereinis applied to the aluminum surface of the reflection layer 26 to athickness of about 2 μm and cured to form the blue transmission layer28, thereby obtaining the reflector 22 for white/blue display.

The resultant reflector 22 for white/blue display is bonded to thesecond substrate 14 of the liquid crystal display panel 11 fabricated asdescribed above with a transparent adhesive material.

The liquid crystal display 20 is thus completed.

—Operational Advantages of Liquid Crystal Display 20—

According to the liquid crystal display 20 fabricated as describedabove, like the liquid crystal display 10 of Embodiment 1, when lightincident from the front is specularly reflected, light specularlyreflected by the cholesteric liquid crystal layer 15 and blue lightreflected by the back are combined, thereby displaying good white color.Also, in focal conic regions of the cholesteric liquid crystal layer 15,the color of the blue diffusion layer is clearly visible. Hence, goodwhite/blue color is displayed. Even when viewed at an oblique angle, thedisplay screen can be viewed with a good viewing quality.

Embodiment 3

A liquid crystal display 30 of Embodiment 3 of the present inventionwill be described in detail with reference to the drawings.

(Configuration of Liquid Crystal Display 30)

FIG. 3 is a cross-sectional view of the liquid crystal display 30 ofEmbodiment 3 of the present invention.

The liquid crystal display 30 includes a liquid crystal display panel 31and a reflector 32 for white/blue display.

The liquid crystal display panel 31 includes a first substrate 33 placedon the display plane side, a second substrate 34 opposed to the firstsubstrate 33, and a cholesteric liquid crystal layer 35 that is placedbetween the first and second substrates 33 and 34 and includescholesteric liquid crystal molecules whose selective reflection color isyellow.

The configuration of the liquid crystal display panel 31 is the same asthat of the liquid crystal display panel 11 in Embodiment 1 describedabove except that the alignment film is not rubbed. That is, thecholesteric liquid crystal molecules of the liquid crystal display panel31 are aligned in a non-rubbing manner.

The reflector 32 for white/blue display includes a reflection layer 36and a blue transmission layer 38, in which the blue transmission layer38 is opposed to the second substrate 34.

As the reflection layer 36, a plastic film such as a polyethyleneterephthalate (PET) film with a metal such as silver and aluminumevaporated thereon, or a smooth, thin metal film obtained by drawing ametal, such as aluminum foil, for example, is used, forming a minorsurface. If the metal (evaporated) surface as the mirror surface issusceptible to deterioration from oxygen, water, and the like, aprotection layer may be formed on the metal (evaporated) surface foranti-deterioration. Such anti-deterioration measures should be takenappropriately depending on the type of the metal and the desireddurability.

As the blue transmission layer 38, an acrylic resin with a blue pigmentsuch as copper phtalocyanine (CuPc), for example, mixed therein isformed on the acrylic diffusion material.

The angular dependence of scattered light intensity of the reflector 32for white/blue display configured as described above is made equivalentto the angular dependence of scattered light intensity of thecholesteric liquid crystal layer 35.

(Method for Fabricating Liquid Crystal Display 30)

Next, a method for fabricating the liquid crystal display 30 ofEmbodiment 3 of the present invention will be described.

(Formation of Liquid Crystal Display Panel 31)

The liquid crystal display panel 31 is fabricated in a manner similar tothat described above in Embodiment 1. Note however that in Embodiment 3,the alignment film is not rubbed.

(Formation of Reflector 32 for White/Blue Display)

A PET film is prepared, and aluminum is evaporated on the surface of thePET film to about 100 nm, for example, to form the reflection layer 36.

An acrylic resin with about 3 wt % of copper phtalocyanine mixed thereinis applied to the aluminum surface of the reflection layer 36 to athickness of about 2 μm and cured to form the blue transmission layer38, thereby obtaining the reflector 32 for white/blue display.

The resultant reflector 32 for white/blue display is bonded to thesecond substrate 34 of the liquid crystal display panel 31 fabricated asdescribed above with a transparent adhesive material.

The liquid crystal display 30 is thus completed.

—Operational Advantages of Liquid Crystal Display 30—

According to the liquid crystal display 30 fabricated as describedabove, like the liquid crystal display 10 of Embodiment 1, when lightincident from the front is specularly reflected, light specularlyreflected by the cholesteric liquid crystal layer 35 and blue lightreflected by the back are combined, thereby displaying good white color.Also, in focal conic regions of the cholesteric liquid crystal layer 35,the color of the blue diffusion layer is clearly visible. Hence, goodwhite/blue color is displayed. Even when viewed at an oblique angle, thedisplay screen can be viewed with a good viewing quality.

Embodiment 4

A liquid crystal display 40 of Embodiment 4 of the present inventionwill be described in detail with reference to the drawings.

(Configuration of Liquid Crystal Display 40)

FIG. 4 is a cross-sectional view of the liquid crystal display 40 ofEmbodiment 4 of the present invention.

The liquid crystal display 40 includes a liquid crystal display panel 41and a reflector 42 for white/blue display.

The liquid crystal display panel 41 includes a first substrate 43 placedon the display plane side, a second substrate 44 opposed to the firstsubstrate 43, and a cholesteric liquid crystal layer 45 that is placedbetween the first and second substrates 43 and 44 and includescholesteric liquid crystal molecules whose selective reflection color isyellow.

The configuration of the liquid crystal display panel 41 is the same asthat of the liquid crystal display panel 11 in Embodiment 1 describedabove except that the alignment film is not rubbed. That is, thecholesteric liquid crystal molecules of the liquid crystal display panel41 are aligned in a non-rubbing manner.

The reflector 42 for white/blue display includes a blue hologram, whichis opposed to the second substrate 44.

The blue hologram (reflector 42 for white/blue display) includes a lightcuring resin layer made of a plastic film such as a PET film having apredetermined pattern of irregularities formed thereon, a metal filmmade of silver and aluminum evaporated on the light curing resin layer,an acrylic resin with a blue pigment such as copper phtalocyanine(CuPc), for example, mixed therein formed on the metal film, and thelike.

The angular dependence of scattered light intensity of the reflector 42for white/blue display configured as described above is made equivalentto the angular dependence of scattered light intensity of thecholesteric liquid crystal layer 45, as discussed above with referenceto FIG. 5, for example.

(Method for Fabricating Liquid Crystal Display 40)

Next, a method for fabricating the liquid crystal display 40 ofEmbodiment 4 of the present invention will be described.

(Formation of Liquid Crystal Display Panel 41)

The liquid crystal display panel 41 is fabricated in a manner similar tothat described above in Embodiment 1. Note however that in Embodiment 4,the alignment film is not rubbed.

(Formation of Reflector 42 for White/Blue Display)

A resin composition including a light curing resin is applied to a PETfilm and dried to form the light curing resin layer. A stamper having apattern of fine irregularities is placed on the resin layer and pressed,to transfer the pattern of irregularities to the resin layer.

The resin layer having the irregularities formed thereon is thenirradiated with an active energy ray such as ultraviolet light, to fixthe pattern of fine irregularities to the resin layer. Aluminum is thenevaporated on the patterned surface of the resin layer to about 100 nm,for example.

An acrylic resin with about 3 wt % of copper phtalocyanine mixed thereinis then applied to the aluminum surface to a thickness of about 2 μm andcured, thereby obtaining the blue hologram (reflector 42 for white/bluedisplay).

The resultant reflector 42 for white/blue display is bonded to thesecond substrate 44 of the liquid crystal display panel 41 fabricated asdescribed above with a transparent adhesive material.

The liquid crystal display 40 is thus completed.

—Operational Advantages of Liquid Crystal Display 40—

According to the liquid crystal display 40 fabricated as describedabove, like the liquid crystal display 10 of Embodiment 1, when lightincident from the front is specularly reflected, light specularlyreflected by the cholesteric liquid crystal layer 45 and blue lightreflected by the back are combined, thereby displaying good white color.Also, in focal conic regions of the cholesteric liquid crystal layer 45,the color of the blue diffusion layer is clearly visible. Hence, goodwhite/blue color is displayed. Even when viewed at an oblique angle, thedisplay screen can be viewed with a good viewing quality.

INDUSTRIAL APPLICABILITY

As described above, the present invention is applicable to liquidcrystal displays.

1. A liquid crystal display, comprising: a transparent first substrateplaced on the display plane side; a transparent second substrate opposedto the first substrate; a cholesteric liquid crystal that is placedbetween the first and second substrates and whose selective reflectioncolor is yellow; and a reflector for white/blue display opposed to thesecond substrate, wherein the angular dependence of scattered lightintensity of the reflector for white/blue display is equivalent to theangular dependence of scattered light intensity of the cholestericliquid crystal.
 2. The liquid crystal display of claim 1, wherein thereflector for white/blue display includes a reflection layer, ascattering layer, and a blue transmission layer formed one upon anotherin this order, and the blue transmission layer is opposed to the secondsubstrate.
 3. The liquid crystal display of claim 1, wherein thereflector for white/blue display includes a reflection layer having apredetermined scattering angle and a blue transmission layer formed oneupon the other, and the blue transmission layer is opposed to the secondsubstrate.
 4. The liquid crystal display of claim 1, wherein thecholesteric liquid crystal is aligned in a non-rubbing manner, and thereflector for white/blue display includes a reflection layer and a bluetransmission layer formed one upon the other, and the blue transmissionlayer is opposed to the second substrate.
 5. The liquid crystal displayof claim 1, wherein the cholesteric liquid crystal is aligned in anon-rubbing manner, and the reflector for white/blue display includes ablue hologram.